This invention relates to devices for lifting and transporting heavy objects and is particularly concerned with such devices of the kind described in British Pat. Nos. 1297382 and 2069454 and comprising a base frame having around wheels, an upper frame slidable vertically on said base frame and provided with means for clamping an object thereto, a manually operable lever pivotally mounted on said base frame for movement about a horizontal axis to raise said upper frame and releasable means for locking said upper frame in its raised position.
The releasable locking means usually comprises a catch rotatably mounted on the upper frame and an abutment mounted on the base frame and operable, in response to upward movement of the upper frame relative to the base frame, to rotate the catch into locking engagement with a shoulder on the base frame.